CVE-2026-59922

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 71% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this weekElevated
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a run of closed tilde, equals-sign, or caret marker pairs around a character causes quadratic work in src/mistune/plugins/formatting.py when the strikethrough, mark, or insert plugin scans for matching markers from each possible start position, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
28.7%
KEV
Not listed

Published

July 8, 2026

Last Modified

July 9, 2026

Advisory Details (3)

Auto-updated Jul 8, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github Patch Available🟡 PoC Available

plugins/formatting: quadratic-time parsing on long runs of `~~x~~`, `==x==`, and `^^x^^` markers (strikethrough / mark / insert) · Advisory · lepture/mistune · GitHub

https://github.com/lepture/mistune/security/advisories/GHSA-c8j7-8cv4-2xmq
github_release Patch Available

v3.3.0

Patch available: lepture/mistune v3.3.0

https://github.com/lepture/mistune/releases/tag/v3.3.0
github_commit Patch Available

commit 96d0f57f8fe9 (lepture/mistune)

Patch available: lepture/mistune v3.3.0 (contains commit 96d0f57f8fe9)

https://github.com/lepture/mistune/commit/96d0f57f8fe9eeb06bb4cff521962a27d7c402e7

Vendor Advisories for CVE-2026-59922(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 12× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-11 16:35 UTCEG score recompute
  2. 2026-07-11 08:27 UTCEPSS rescore
  3. 2026-07-11 08:27 UTCEPSS rescore
  4. 2026-07-11 04:35 UTCEG score recompute
  5. 2026-07-10 16:35 UTCEG score recompute
  6. 2026-07-10 04:33 UTCEG score recompute
  7. 2026-07-09 19:10 UTCEPSS rescore
  8. 2026-07-09 19:10 UTCEPSS rescore
  9. 2026-07-09 16:26 UTCEG score recompute
  10. 2026-07-09 04:24 UTCEG score recompute
  11. 2026-07-08 16:25 UTCEG score recompute
  12. 2026-07-08 16:24 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-59922?
CVE-2026-59922 is a high vulnerability published on July 8, 2026. Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a run of closed tilde, equals-sign, or caret marker pairs around a character causes quadratic work in src/mistune/plugins/formatting.py when the strikethrough, mark, or insert plugin scans for matching markers from each…
When was CVE-2026-59922 disclosed?
CVE-2026-59922 was first published in the National Vulnerability Database on July 8, 2026, with the most recent update on July 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-59922 actively exploited?
CVE-2026-59922 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 28.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-59922?
CVE-2026-59922 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-59922?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59922, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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